Relief means for pressure cookers



Jan. 12,1926. x 1,569,187

' J. R. JEWELL RELIEF MEANS FOR PRESSURE GOOKERS Filed June 25, 1921 INVENTOR. J5me R Jwel/ i RNEY a Patented Jan. 12, 1926.

UNIT D STATES PATENT OFFICE.

33553 3. mm, 01 LINCOLN, NEBRASKA, ASSIGNOR '10 NATIONAL MANUFACTUR- ING COMPANY, OF LINCOLN, NEBRASKA, A CORPORATION'OF NEBRASKA.

BELIEF MEANS FOR PRESSURE COOKIES.

Application med June 25, 1921. Serial no. new. i

To all whom it may concern:

Be it known that I, Jesse B. JEWELL, a citizen of the United States, residing at Lincoln, in the county of Lancaster and State of Nebraska, have invented certain new and useful Improvements in Relief eans for Pressure Cookers, of which the following is a specification.

This invention relates to improvementsin pressure cookers, and more particularly to means for relieving any excess pressure that might be built up within the cooker during its use, to eliminate danger of explosion,'and the like, resulting from excess pressure therein.

Among the objects of my invention is to improve generally in the construction of .covers for pressure cookers; further to pro vide improved means to permit the escape 0 of steam, 'or the like, from within the cooker at such times as the pressure of the same exceeds a predetermined amount; further to provide an improved form of ball type safety valve for pressure cookers; further to produce an improved auxiliary release to function in the event the main safety valve becomes stuck, or for other reasons refuses to operate; further to provide a valve for pressure" cookers that shall be positive in operation, easy of adjustment, accesslble, andat the same time entirely fool proof; further; to provide a valve that will be an absolute safe-guard against defective presa sure gauges, and to reduce the'cost of manings, and while I have shown therein'a preferred embodiment, I desire the same to be understood as illustrative only, and notaslimiting the scope of my invention.

In the drawings Fig. 1 is an elevation of a. pressure cooker embodying my invention.

Fig. 2 is an enlarged plan view looking down on Fig. 1.

openings 14 for the .ity of ufacturing, and the number of necessary parts illustrated in the accompanying draw escape of Fig. 3 is an enlarged vertical section taken on line 33 of Fig. 2.

Fig. 4 is an elevation detail of my improved ball type safety valve- Referring to the drawings, and more particularly Fig. 3, my improved ball type safety valve comprises the threaded base portion 1, secured by the threaded to cover 3, for connection with the interior of the steam chamber of the pressure cooker. Extending through 1, is a longitudinal opening 4, terminating at its upper end in the steam cavities 5 and 6, forming primary valve seat 7, and secondary'seat 8. Ball 9 rests firmly on pristem 2 and base member .0 stem 2,

mary seat 7 while a slight amount of clear-. v

ance is provided between this ball and the secondary seat 8. Secured upon valvebase 1, by threads, or the like, is the hood or casing 10, having an upwardly extending tubular portion 11 of smaller diameter, which at its upper end is internally threaded at 12 to receive nut 13, having a series of reception of .a wrench to rotate the same as desired.

Secured to and extending upwardly from ball 9 is stem 13 provided intermediate of its ends with flange 14, between which flange and the inner end of nut 13 is seated a coil spring 15, normally tending to hold ball 9 against primary seat 7. Formed in the hood 10 between the body portion thereof and the tubular portion 11, are a pluralopenings 16, through which steam, or the like, may escape from inside of the valve to the exterior. As will be readily understood nut 13 functions as an adjusting nut to adjust the tension of coil spring 15,. as desired.

The. operation of this valve is as follows: When the pressure within the cooker reaches a predetermined amount ball 9 is slightly lifted from primary seat 7, as the result of accumulated pressure in cavity 5, which is exerted against the lower face of ball 9. As soon as ball 9 is slightly raised, cavity 6 becomes filled with steam, and the much larger area enclosed by-secondary seat 8 is exposed to steam pressure, whereupon the spring pressure is greatly overcome and the ball lifted much higher, thus allowing a full steam through passage 4, cavities 5 and 6, and openings 16, in the valve cover or casing 10. As soon as suificientjsteam has escaped, so that pressure in cavity 6 against the area of the ball exposed by secondary seat 8 is no longer sufiicient to over come the pressure of spring from above, the ball is forced downwardly diminishing the flow of steam bet-ween'the ball \and the grimary seat 7, which in turn further iminishes the steam pressure against the large exposed area, causing the ball to return suddenly to primary seat 7. This results in a quick, positive and explosive opening of the valve when an excess pressure accumulates within the cooker, and. an

abrupt sudden closing of the valve when the excess amount of pressure has been re-' lieved.

'It is of importance to note that. the valve theball 9,'and is provided with the spring seating flange 14, which is also integral with or firmly secured to this stem. Also that spring flange seat 14 slips readily into valve cover extension 11, and that stem 13 slips readily through the opening in adjusting nut 13, both serving to guide and maintain the motion of ball 9, and stem 13 in a vertical direction, and after valve operation to always cause the same portions of the ball surface to return to contact with seat 7. This insures an effective seating of the valve and eliminates danger of erratic action of the valve and leakage of steam because of irregularities on the surface of the ball. Adjusting nut 13 may be set to any de-' sired adjustment at the factory, and due to I the requirement of a special kind of wrench to change-this setting, such adjustment cannot be readily tampered with. This construction greatly facilitates the ready' ad-- justment of the valve at the factory (and afterwards if the special wrench is provided), and eliminates such undesirable operations as grinding or clipping ofi' ends of the spring, compressing or "stretching the 5 rings to lessen or increase the tension t ereof, thus saving considerable time in-the manufacture and adjustment of this form of valve, and at the same time very materially increasing the efficiency of valve operation.

' Guiding stem 13 passing through adjusting nut 13' affords a ready means for manually lifting ball 9 from its seat, if desired, for the purpose of quickly releasing the steam pressure in the cooker, ortheWac'uum created therein, after the same has been allowed to cool. Said release of vacuum bein necessary before the cover can be removed from the cooker. 7

As will be noted the valve hood or casing 10, is secured to the base 1 by means of'threads, as a ,result of which rotation of the hood or casing 10, will change the tension of coil spring 15 in accordance with the direction of of twenty pounds rotation. Referring to Fi 4, it will be noted that an index mark 1 is provided on the exterior of base 1, and graduations. 18 are formed on hood 10, these graduations bearing such relation to index mark 17 that when they are caused to respectively register therewith, will indicate the corresponding gauge pressure within the cooker. For illustration, the parts as positioned in Fig. 4 indicate a gauge pressure in the'cooker (per square inch, while if the hood be rotate to the right until mark indicated as fifteen registers with. index mark 17,. the setting of the spring will be such as to cause 0 ening of the valve, when the pressure wit in the cooker reaches fifteen pounds per square inch.

I have also provided an improved auxiliary means in t e form of a secondary relief valve to function should the pressure within the cooker reach a point in excess of that for which the ball valve is set, through the latter becoming stuck, or for other reasons,

refusing to operate. This auxiliary or secondary relief means is indicated generall at S in'Fig. 3, the construction of which is as follows: An opening 20 of considerable size is provided in the top of the ressure cooker cover, the edges of which are velled to form valve seat 21, to receive valve 22,

having downwardly projecting stem 23, lon-" gitudinally slidable in an opening in cross bar 24. The upper face of valve 22 is rovided with projection 25, over whic is seated a coil spring 26, which .is compressed between the 11 per face of valve 22 and the under face of hood or casin 27, a sufficient amount to give desired reslstance to valve 22. Screwed into suitable openings in cover 3 are upwardly projecting studs 28, formed at their upper ends with a headed portion 29, adapted to pass through the enlarged opening 30, formed at the end of slot 31. From this it will be understood thatiin applying hood or casing 27 sprin 26 is first placed over projection 25 and hoo 27 is then moved downwardly until heads 29 pass through enlarged openings 30 of bayonet slots 31, after which hood 27 will be rotated to bring heads 29 to the rear of slots 31, which will thus hold hood 27 in osition with spring 26, suitably compresse and at the same time provide an esca e for such steam that mayv pass through va ve 22 by way of the pressure within the cooker, thus eliminating all dangerof explosion of the cooker eonie? sure therein.

Having now described my invention, I claim v 1. In a pressure cooker a cover, studs secured in said cover and extending upwardly therefrom, heads formed on said studs, a hood provided with bayonet slots adapted to receive the heads ofsaid studs, and a spring positioned between said hood and valve and compressed when said heads 7 are passed through the enlarged portion of .said bayonet slots andthe hood rotated.

2. In a pressure cooker an auxiliary or secondary pressure relief means'comprisin a valve seat of considerable diameter formed in the cover, a valve on said seat, studs in said cover, heads on said studs, a spring bearing centrall on said valve, a hood having bayonet slots .a apted to receive the headed ends of said studs, so thatwhen said ends are passed through said bayonet slots and the hood rotated, the spring will be held compressedbetweenthe hood and valve, and

means for guiding the movement of said valve in a rectilinear direction.

3. A relief valve com rising a body portion having a seat, a valire oo-operable with the seat and having a guide stem, means cooperable with the stem for guiding the] movement of-the valve and stem, a hood, means detachably connecting the hood to the body in spaced relation thereto for providing an escape opening between the hood and the body, and a spring interposed between and pressing a ainst the valve and the hood to normally ho d the valveto it's seat.

4. A rehef valve com rising a body portion having a seat, a vali e co-operable with the seat and having a guide stem, means cooperable with the stem for guiding the movement of the valve and stem, a hood, studs detachably fastened to the body, said hood being detachably connected to the studs and in spaced relation to the body for providing an escape space between the hood and the body, and a spring pressing against thetvalve to normally hold the valve to its sea 5. A relief valve comprising a body portion having a seat, a valve co-operable with the seat and having a guide stein, means cooperable with thestem for guiding the movement of the valve and stem, a hood, means .including pin and slot connections for detachably connecting the hood to the body whereby the hood may be uickly attached and detached, said hood eing provided with a flange spaced from the body for pro-' viding an escape opening between the flange and the body, and a spring pressing against the valve to normally hold the valveto its seat.

6. A relief valve comprising a body portion having a seat, .a valve oo-operable with the 'seat, means reacting against the hood and preming a ainst said valve for resiliently holding the va ve to the seat, a hood for the valve, means connecting the hood to the body in spaced relation thereto for providing an escape opening between the hood and body, said means and hood coo crating to permit ready detachment. of t e hood without the removal of said means.

7. A relief valve comprising a body portion having a seat, a valve co-operable with the seat, means for resiliently pressing the valve to the seat, a hood for the valve, means connecting the hood to the body in spaced relation thereto and for providing an escape opening between the hood and body, said means comprising studs detachably secured to the body and the hood, said hood being detachably connected to said studs without the removal of said studs.

' 8. A relief valve comprising a body portion having a seat, a valve co-operable with the seat, means for resiliently pressing the valve to the seat, a hood for the valve, means connecting the hood to the body in spaced relation thereto and for providing an escape opening between the hood and body, said means comprising headed studs secured to the body and bayonet slots provided in thehood and co-operating with the heads of the studs for detachable connection of the hood to the studs.

In witness whereof, I hereunto my name to this specification.

' JESSE R. J EWELL.

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